In order to assure the safe operation of jet aircraft, a variety of alcohols are being added to the fuel for the purpose of preventing formation of ice particles caused by the freezing of traces of water which may be present in the fuel. As an example of this, ethyleneglycolomethylether may be added to the jet fuel in quantities of one tenth to fifteen hundredths of a percent by volume, for the purpose of inhibiting the formation of ice. Because of the relationship between the addition of ice inhibitors to the fuel and the safety of the flight of the aircraft, there has been a long felt need for an easy to employ method to determine accurately and instantaneously the quantity of alcohol in jet fuel.
One method of testing jet fuel for alcohol content known to the art is described in West German Patent No. DT-PS-2,261,200. This method uses a small testing tube. The dimensions of the tube used are chosen so that the time of reaction of the chemical indicator can be determined in advance. This procedure has been known to the art and is commonly employed in column type chromotography. An emulsion matrix is formed, for example, by saturating a fine grained gel (with grain sizes preferably between three tenths and five tenths of a millimeter) with sodium monovanadiate and then drying it. Subsequent to this, water is added to the mixture to provide a certain level of moisture content. This emulsion matrix is then poured into the small tube and can be stored for long periods of time. An organic acid such as acetic acid can be added to the mixture at this time or alternately added to the mixture just prior to the testing of the jet fuel.
A solution of 8-Hydroxyquinoline in benzine or in any other appropriate organic solvent which is free of OH-group chemicals, must be available in certain pre-measured quantities at the time of the testing of the fuel. Immediately before the testing, the 8-Hydroxyquinoline solution must be poured into the tube, thereby causing a portion of the emulsion matrix, which was already present in the tube, to become green in color. At this point the fuel to be tested is passed through the small tube, which is open at both ends. This causes a certain amount of the emulsion matrix to become discolored. The proportion of the matrix which becomes discolored is directly related to the alcohol content of the fuel. At a higher alcohol content level, more of the matrix becomes discolored than at a lower alcohol content level. Thus, the alcohol content of the jet fuel tested can be determined.
One notable disadvantage of the above described method is that it is awkward. Immediately prior to the testing of the fuel, a separate reactant in a specified concentration and quantity first must be poured into the tube before the fuel can be tested. Because of the encumbrance associated with this method, the possibility of making mistakes and errors is enhanced.
Another critical disadvantage of the above stated prior art method is that when the 8-Hydroxyquinoline is added to the tube just prior to the testing of the fuel, only the upper portion of the emulsion matrix in the tube becomes green colored. The remainder of the emulsion matrix will take on a green color only when the fuel to be tested is added. Subsequent to this reaction, a portion of the now entirely green emulsion matrix will discolor, the amount of discoloration indicating the alcohol content of the fuel. Because of this two phase reaction, there is a distinct possibility that the observer will draw the wrong conclusion that the alcohol content in the fuel causes the entire emulsion matrix to become discolored when, in reality, it is the 8-Hydroxyquinoline which causes the entire emulsion matrix to take on a greenish color and the alcohol content in the fuel is only responsible for causing the greenish colored emulsion matrix to take on a different color.
The present invention, to be disclosed and described as follows, overcomes the problems and disadvantages that are associated with the prior art method and provides a simple and easy to use method and apparatus that eliminates the necessity of having to add any chemicals to the tube in pre-measured quantities just prior to the testing of the jet fuel, and provides more accurate results than were obtained with the prior art method.